Unconventional resources such as shale gas currently account for 30% of U.S. gas production, and the unconventional gas production is expected to increase in the next 25 years. Production of unconventional oil and gas needs relatively large volumes of water and generates waste stream. Handling of these large volumes of produced water and the associated costs have limited the development of both conventional and unconventional reservoirs. Development of oil and gas resources is becoming increasingly constrained due to environmental concerns and regulations, new methods are needed for the efficient handling of produced water using environmentally acceptable and economically viable technology.
Development of new technology for managing waters generated in association with oil and gas production is expected to reduce the cost and increase the efficiency of producing these resources while minimizing environmental impact. This is a critical issue for the sustainability of oil and gas drilling and for expansion in emerging areas.
Flowback water from drilling operations such as hydraulic fracturing typically contains inorganic metal salts, organics, and biocides. Such components are among the more difficult to treat and tend to limit the utility of the water for reuse or other purposes. Mercury, arsenic, and selenium present a difficult challenge for many types of current treatment options, and concentrations of these constituents in some produced waters can be relatively high.
Current technologies for flowback water treatment, such as reverse osmosis (RO) and electrodialysis, for treating oil and gas produced waters, has been limited by the presence of relatively large amounts of dissolved solids and organics in such waters which can cause rapid and severe deterioration of filtration membranes.
Most current technologies for treating produced waters are relatively costly, especially considering the large volumes of water produced and energy requirements, and are often unable to achieve the new, rigorous water-quality standards. New, low cost, and readily implemented approaches are needed for management of water associated with development of conventional and unconventional oil and gas reserves.